1. DNA Structure & Chromosomes
Deoxyribonucleic Acid pp

2. DNA Stores and transmits genetic information to make proteins
Made up of repeating units of nucleotides

3. Location Prokaryotes: floats in cytoplasm
Eukaryotes: wrapped around proteins in the nucleus

4. DNA Structure Nucleotides have three parts: Deoxyribose Sugar
Phosphate Group
Base

6. Complementary Base Pairing
Purine bonds to Pyrimidine
A bonds to T
G bonds to C

7. DNA Bases Purines: Two-ringed bases Pyrimidines: One-ringed Bases
Adenine and Guanine
Pyrimidines: One-ringed Bases
Thymine and Cytosine

8. DNA Bonds
Two strands (at the bases) are held together by weak hydrogen bonds.
The sugar phosphate backbone is held together by covalent bonds

9. Double helix: DNA is double-stranded and coiled like a spiral staircase.
Backbone is like the railing and the bases are the steps.

10. Chromosome Structure Coiled and compact DNA in nucleus
DNA wrapped tightly around proteins called histones

11. Chromatids: two halves of a dividing chromosome
Chromatids joined by a centromere

13. Chromosome Number
Sex chromosomes: determine sex of the organism (X or Y)
female: XX male: XY
Autosomes: all other chromosomes
All organisms have two copies that are homologous

14. Haploid vs Diploid Haploid (n): only 1 set of chromosomes (n=23)
Typically gamete cells (eggs or sperm)

16. Diploid (2n): having 2 sets of chromosomes (2n=46)
Morphologically similar (homologous)
One set from mom and one set from dad
2 haploid cells (sperm and egg) can combine to make a diploid (zygote)